"I've always considered Children's Mercy to be Kansas City asset, and we need to take care of it," Riggle said.

"(The celebs) love coming to KC. They love eating barbeque. They love all the events. But all them say the best part of the weekend is visiting the hospital and spending time with the kids," Rudd said. "That's why we're here. That's why they ask to come back."

Over the years, Big Slick has donated more than $1.4 million to Children's Mercy Hospital. That money has helped expand its Bone Marrow Transplant Unit and family/play rooms. It's also helped add entertainment systems to every oncology hospital room and purchase more than $500,000 in advanced early detection equipment.